In the art there is a substantial amount of conveyor belts made from a plurality of substantially identical belt links, where each modular belt link is provided with means at leading and trailing edges for hingely and/or flexibly connecting two adjacent links such that a substantially continuous conveying surface is provided. The means for connecting adjacent links may for example be eye parts projecting from the leading or trailing edges where apertures are provided laterally in the eye parts such that eye parts of one modular belt link may be intermeshed with eye parts on an adjacent belt link whereby the apertures are superposed such that a connection pin just like a hinge may hingely connect to adjacent belt links.
In other embodiments the eye parts are provided with protrusions which extend laterally from the eye parts along one edge and along the opposite edge of the modular belt link the eye parts are provided with keyholes recesses which may accommodate the protrusions such that by inserting the protrusions on the eye parts of one modular belt link into the keyhole recesses. On an adjacent modular belt link a hinge like connection is created between two adjacent modular belt links.
In the art there are various variations of these types of connections and they all are well-proven and reliable, but also all possess a number of drawbacks which over the years have been sought addressed by various inventions by various modifications to the design of the eye parts, connecting pins etc.
A common drawback of these types of modular belt links is the fact that the laterally arranged apertures in the eye parts as well as the inserted pin create positions where it is very difficult to thoroughly clean the conveyor belt which especially for application in the food industry is very important. For these types of conveyor belts it is very difficult to maintain a high hygienic standard. In the art it is common to either at regular intervals dismantle the belt and soak it in cleaning solutions or stop the belt on the conveyor chassis for a period of time and soak it in cleaning liquids in-situ. These solutions naturally make it impossible to use the conveyor belt, while the cleaning process is carried out, and as such the profitability of the construction is not optimal.
Moreover, the cleaning process, although cleaning liquids are used that may effectively exterminate bacteria and the like, does not reliably remove all debris from the places that are difficult to reach, and although the hygienic standard bacteria-wise is achieved, the debris which has been hiding in the places that are difficult to reach may become dislodged and end up in the food product as pollution.
A further disadvantage with conveyor belts of this type is the fact that as a working surface the eye parts are not optimal, in that they provide an uneven surface to work on. Therefore, cutting action, for example during cutting up of animals, may not be carried out reliably. In the art this problem has been addressed by various special modular belt links where the upper surface is substantially continuous by providing a cover plate over the eye parts which in turn has resulted in narrow slits between adjacent modular belt links. These narrow slits have the disadvantage that knives or other thin objects may become lodged in the slit. This in itself is not a problem, as it is relatively easy to withdraw the object from the slit when the conveyor belt is stationary, but during production processes the conveyor belt is constantly moving and when the knife for example becomes stuck in a slit the angle between the knife's blade and the conveyor belt changes rapidly such that in most cases the tip of the knife will be broken off the knife with the risk that the tip ends up in the food products. For these purposes in a number of production lines magnetic sensors are installed on the finished product in order to detect magnetic debris from the production line.